1. Field
The disclosed technology relates to a thin film transistor, and a pixel and an organic light emitting diode (OLED) display including the same, and in detail, relates to a thin film transistor with an improved hysteresis characteristic, and a pixel and an organic light emitting diode (OLED) display including the same.
2. Description of the Related Technology
Various display devices for displaying a motion picture and text have been developed. Such devices include, for example, a flat panel display such as a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), or an organic light emitting diode (OLED) display.
Among the flat panel displays, the organic light emitting diode display, which displays images by using organic light emitting diodes (OLEDs) that generate light by recombining electrons and holes, has a fast response speed, has low power consumption, and has excellent emission efficiency, luminance, and viewing angle, such that it has recently been favored.
In general, the organic light emitting diode (OLED) display may be classified as either a passive matrix OLED (PMOLED) display or an active matrix OLED (AMOLED) display according to a method of driving an organic light emitting diodes (OLEDs). An active matrix display selectively turns the pixels on and off and is mainly used in because of resolution, contrast, and operation speed.
Performance of the flat panel display is determined by various metrics, such as whether a clear and clean image is displayed without motion blur when displaying a motion picture or moving text with the motion picture. Motion blur is generated due to the reaction speed of liquid crystal in a case of the liquid crystal display (LCD).
However, in an organic light emitting diode (OLED) display, atoms of the organic emission layer are excited and light emits, so motion blur due to the reaction speed is not generated, however the motion blur is generated by a delayed response time because of a hysteresis characteristic of a driving transistor controlling a current applied to the organic emission layer.
In detail, in an organic light emitting diode (OLED) display, a driving transistor transmits a driving current of a data voltage level according to a data signal to the organic emission layer, and the gray level of the current data may not be displayed due to the hysteresis characteristic of the driving transistor. Particularly, when the current amount is quickly changed from a low grayscale to a high grayscale, or from the high grayscale to the low grayscale, the current corresponding to the grayscale change is normally transmitted according to the hysteresis characteristic of the driving transistor and the normal luminance is not displayed such that the motion blur appears.
Accordingly, research into the improvement of the hysteresis characteristic of the driving transistor to display a clear image of high display quality by eliminating motion blur in the organic light emitting diode (OLED) display is required.
The above information disclosed in this Background section is only for enhancement of understanding of the background and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.